Abstract: In this report we present the multi-disciplinary
work performed in the first phase of the COHSY project concerning generation
of models and analysis of {\em hybrid} systems -- mathematical models
including both continuous and discrete elements. The participants of the
project were SAAB Military aircraft, Volvo aerospace, and VOAC hydraulics, as
well as three departments from Linköping University: Computer Science,
Electrical engineering and Mechanical engineering. The report addresses
modelling and formal verification of a fictitious system, the landing gear of
an aircraft referred to as JAS-95 Lite, which involves hydro-mechanical and
electro-mechanical sensors and actuators as well as electronic and software
modules performing diagnosis and control. The technical system, is moreover
in dynamic interaction with a human operator (the pilot). The main aim of
this work has been to mathematically prove that specified requirements are
satisfied by given design specifications for the controller and alternative
models for the physical environment. An architectural model is used to
facilitate the combination of alternative configurations. The report provides
a summary of several tracks of activity, a major one being the application
and illustration of state of the art techniques in physical modelling of the
hardware, and mathematical modelling and verification of the closed loop
system. The languages used for modelling range from engineering schematic
diagrams to Bond Graphs, hybrid transition systems, hybrid automata, and the
temporal logic Extended Duration Calculus. It also provides some insights
into modelling in synchronous languages for high level specification of
real-time programs -- the interest being the investigation of the
applicability of tools available for analysis and subsequent code generation
from high level designs. Two languages from this family are examined in the
context of the case study: discrete models in Esterel and timed models in
statecharts as implemented in the tool Statemate.